In recent years, regenerative power generated by regenerative brakes of trains is used as running power for other trains via a feeder in a DC feeding network. In such a DC feeding network, a feeding voltage increases when the regenerative power exceeds the running power in the same transformation zone, and the feeding voltage decreases when the regenerative power falls below the running power. For example, a conventional technique has been disclosed in which the surplus regenerative power occurring when regenerative power exceeds running power is transformed into AC power to be supplied to a station load via an AC system, the power that exceeds the consumption power for the station load is stored in a secondary battery, and the secondary battery is discharged when a feeding voltage is decreased to supply DC power to a feeder, thereby stabilizing the feeding voltage and also effectively using the surplus regenerative power to an extent that prevents a reverse power from flowing to the AC system (for example, Patent Literature 1).